Lula unifies Brazil's left, but questions remain about its future without him

BRASILIA, July 31 - When Brazilian President Luiz Inacio Lula da Silva takes the stage at the country's Workers Party convention on Sunday to accept his seventh, and likely final, nomination as a presidential candidate, at the age of 80, he will do so with the Brazilian left more united behind him than at any other point in his decades-long political career.